The present invention relates to boat lifts, and more particularly to boat lifts which each year need to be placed in position in the spring and removed from the water in the fall.
Heretofore, boat lifts in a great variety of styles have been proposed for use adjacent the shore to lift boats out of the water when not in use. A boat lifted out of the water does not need to be tethered, nor is subject to wave motion, nor is subject to bottom discoloration or the like, and thus, such boat lifts have proven to be very popular.
Such boat lifts have been provided with a carriage that vertically lifts the boat upwardly within a frame, a carriage that pivots on a frame, or an angular skid upon which the boat may be slid upwardly. Boat lifts of these types may weigh from a few hundred pounds to a few thousands of pounds. Great weight reduction was achieved relatively recently when such boat lifts were made of aluminum rather than steel.
All of these boat lifts pose the same problem each year to the user in the northern parts of the country where the water freezes. That is, each spring, the boat lift must be placed within the water and positioned as desired and each fall the boat lift must be removed from the water and stored during the winter months.
A great variety of methods have been used to place boat lifts in the water and to remove boat lifts from the water. These include using a variety of watercraft including rowboats, canoes, and pontoon boats beneath the boat lift to float the boat lift into position and to sink the boat lift into position as desired. Some boat lifts even have the capability of utilizing the same winch system that lifts the boat to lift the boat lift onto such watercraft once the watercraft is positioned beneath the boat lift. Thus, the owner of the boat lift must have at his or her disposal suitable watercraft for this purpose.
It is therefore highly desirable to provide an improved boat lift.
It is also highly desirable to provide an improved boat lift which can be more easily positioned in the water in the spring as desired and removed from the water in the fall.
It is also highly desirable to provide an improved boat lift by which placement of the boat lift in the water in the spring and the removal of the boat lift from the water in the fall can be achieved without utilizing additional watercraft or an assemblage of persons.
While it has been herebefore proposed to secure hollow drums onto a boat lift for flotation purposes, such drums have not been widely used for a variety of reasons. Firstly, the drums have to be removed from the boat lift in order to sink the boat lift when positioned in a desired position. Thus, the use of drums is not any more convenient than the use of the auxiliary watercraft as aforedescribed, and may be more dangerous. Secondly, the drums cannot be permanently affixed to the boat lift as the drums can never be made sufficiently less buoyant to sink the boat lift. Thus, they must be attached when desired and removed from the boat lift when the boat lift is in position. Thirdly, it is relatively expensive to provide such drums which will not leak in any condition. When such drums leak and are filled with water, the drums become very difficult to manage, and if attached to the boat lift, add weight to the boat lift rather than to add buoyancy to the boat lift. Fourthly, the use of removable drums, especially with the heavier boat lifts, have proven to be extremely dangerous. Thus, the use flotation drums has not been widespread, and abandoned by most.
It is therefore highly desirable to provide an improved boat lift which can be made buoyant as with attached drums, but does not have any of the disadvantages of drums.
It is also highly desirable to provide an improved boat lift with selective buoyancy which may be permanently secured to the boat lift.
It is finally highly desirable to provide an improved boat lift with all of the above mentioned features.